Dict / Table optional not typing properly. #3360

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1. carsakiller commented on Feb 23, 2026

   

   carsakiller

   on Feb 23, 2026

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   I am unable to replicate. Can you provide your full code snippet and annotations?

   

   My best guess is your did variable is not a string and thus does not satisfy table<string, BazaarDenominationsData>, resulting in denominations being nil, as defined in your annotation:

   

   My Code

   ---@class BazaarCurrencyProperties
   ---@field denominations table<string, BazaarDenominationsData>?
   ---@field pluralName string?
   
   ---@class BazaarDenominationsData
   ---@field value number
   ---@field properties BazaarDenominationProperties
   
   ---@class BazaarDenominationProperties
   ---@field tradeOnly boolean
   ---@field name string
   
   ---@type BazaarCurrencyProperties
   local bcp
   
   local var = "foo"
   
   local isTradeOnly = bcp.denominations[var].properties.tradeOnly
2. carsakiller

   added

   feat/LuaCats AnnotationsRelated to Lua Language Server Annotations (LuaCats)Related to Lua Language Server Annotations (LuaCats)

   feat/type checkRelated to the type checking featureRelated to the type checking feature

   on Feb 23, 2026
3. Safebox36 commented on Feb 23, 2026

   

   Safebox36

   on Feb 23, 2026

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   It looks like you have the same scenario I got in your second screenshot, where it returns unknown as the "type".

   The function looks like this if you want to try and replicate it more accurately:

   Spoiler warning

   local interop =
   {
       currencies = {}
   }
   
   --- @class BazaarCurrencyData
   --- @field symbolPattern string The string pattern used to represent the currency using `%d`. For example: "%d gp", "gold worth %d".
   --- @field properties BazaarCurrencyProperties?
   
   --- @class BazaarCurrencyProperties
   --- @field denominations table<string, BazaarDenominationData>? Alternate object IDs for denominations of the currency. Note: If the value is less than the base, it will only be converted to the base upon reaching a whole value.
   --- @field pluralName string? The plural form of the currency's name.
   --- @field soundId string? The sound effect played when the currency is exchanged.
   --- @field tradeOnly boolean? Hide the currency in the merchant's barter menu.
   
   local function filterBarterMenuCallback(e)
       local merchantData = interop.getMerchant(tes3ui.getServiceActor().reference.baseObject.id)
       if (merchantData) then
           for _, cid in ipairs(merchantData.acceptedCurrencyIds) do
               print("id 1: " .. cid)
               if (e.item.id == cid and e.tile.isBartered == false) then
                   e.filter = not interop.getCurrency(cid).properties.tradeOnly
                   return
               else
                   for did, _ in ipairs(interop.getCurrency(cid).properties.denominations) do
                       if (e.item.id == did and e.tile.isBartered == false) then
                           e.filter = not interop.getCurrency(cid).properties.denominations[did].properties.tradeOnly
                           return
                       end
                   end
               end
           end
       else
           for func, merchantData in pairs(interop.complexMerchants) do
               if (func(tes3ui.getServiceActor().reference)) then
                   for _, cid in ipairs(merchantData.acceptedCurrencyIds) do
                       print("id 2: " .. cid)
                       if (e.item.id == cid and e.tile.isBartered == false) then
                           e.filter = not interop.getCurrency(cid).properties.tradeOnly
                           return
                       else
                           for did, _ in ipairs(interop.getCurrency(cid).properties.denominations) do
                               if (e.item.id == did and e.tile.isBartered == false) then
                                   e.filter = not interop.getCurrency(cid).properties.denominations[did].properties.tradeOnly
                                   return
                               end
                           end
                       end
                   end
                   break
               end
           end
       end
   end
4. tomlau10 commented on Feb 24, 2026

   

   tomlau10

   on Feb 24, 2026

   Last edited by tomlau10

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   This is exactly what @carsakiller trying to illustrate:

   My best guess is your did variable is not a string and thus does not satisfy table<string, BazaarDenominationsData>, resulting in denominations being nil, as defined in your annotation:

   • your did var is integer type, as it is declared as the 1st iter var in ipairs

   for did, _ in ipairs(interop.getCurrency(cid).properties.denominations) do
   -- ^^^^ `did` is `integer` here
       if (e.item.id == did and e.tile.isBartered == false) then
           e.filter = not interop.getCurrency(cid).properties.denominations[did].properties.tradeOnly
           return
       end
   end

   • this doesn't match your @field denominations table<string, BazaarDenominationData>? which requires a string key
   • denominations[<string>] => BazaarDenominationData
     but denominations[<integer>] => unknown

   ---

   Maybe you want to write the annotation as @field denominations table<integer, BazaarDenominationData>?
   or even @field denominations BazaarDenominationData[]? because it is actually an array of BazaarDenominationData ? 🤔

   Furthermore if it is an array, you can access the array element directly as a loop variable:

   for did, denomination in ipairs(interop.getCurrency(cid).properties.denominations) do
       if (e.item.id == did and e.tile.isBartered == false) then
           e.filter = not denomination.properties.tradeOnly
           return
       end
   end
5. Safebox36 commented on Feb 26, 2026

   

   Safebox36

   on Feb 26, 2026

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   Oh I see what I've done now. My mistake.
6. carsakiller commented on Feb 26, 2026

   

   carsakiller

   on Feb 26, 2026

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   Good luck with your project!
7. carsakiller

   closed this as completedon Feb 26, 2026